DE 10 2004 005 994 A1 discloses a labeling machine having an apparatus for feeding of labels, and a labeling unit. The labeling unit has a label container, a glue roller, a rotatable carrier provided with gluable withdrawing segments, and a gripper cylinder. Using such a labeling machine, it is possible to provide containers, such as bottles, with labels. The labeling machine can be configured, for example, as a rotary-table-type machine, a linear machine, or a horizontal-table-type machine. A label-position checking device is disposed in the exit area of the labeled bottles. The label position checking device monitors the desired orientation of the labels on the bottles.
It is known to check that a label is in a correct location relative to design features, such as embossings, on the bottles. It is also known to check neck and body labels for correct alignment, either relative to one another or to the design features. If a label's location deviates beyond a definable tolerance, the label position checking device conveys corresponding signals that trigger a correction device. The correction device then acts on the labeling units so that a correct label position can be achieved. The bottles that do not have a correctly positioned label are ejected via an outward transfer apparatus. The ejection can also take place as a result of the correspondingly generated signal of the label position checking device.
DE 44 41 245 A1 discloses a method for checking labeled vessels. The checking device, which is integrated in a labeling machine, is equipped with a laser distance meter. The laser distance meter can be used to determine whether or not a container has a label. During an active measuring interval the laser beam emitted by the laser distance meter first strikes the surface of a passing bottle and measures the latter's distance from its fixed-position housing. This position forms the constant point of reference.
As soon as the laser beam strikes the surface of the label, there is an abrupt decrease in the instantaneously measured distance. This abrupt decrease arises from and is equivalent to the thickness of the label and to the film of adhesive, if any, between the bottle and the label. This abrupt change of distance is captured in an evaluator and evaluated as a criterion for the presence of a label. Accordingly the evaluator sends either no signal or a signal indicating a good container to a sorting apparatus. If there is no label on the bottle, no abrupt change of distance can be detected. In such a case, the evaluator sends an error signal to the sorting apparatus, which then ejects the unlabeled bottle. This device can only tell whether a label is present on the bottle or not. It cannot determine whether the label is also correctly aligned relative to design features, or whether the label has creases.
DE 10 2006 022 492 A1 discloses a test container for a container checking device. The test container has many first marking rings that surround at least sections of the test container at predetermined, fixed heights. The test container also has many marking lines running in a longitudinal direction of the test container. The first marking rings are each disposed at constant, specified intervals in the longitudinal direction of the test container relative to one another. The marking lines intersect at least a part of the first marking rings. These marking lines are each disposed at predetermined intervals in a peripheral direction of the test container relative to one another. This is intended to facilitate a simplified adjustment of a camera to be changed in the checking device.
Bottles or similar containers are filled with a filling material by a filling apparatus, after which they are passed to a labeling machine. The containers are aligned either at the labeling machine or before they reach the labeling machine. In particular, the containers are aligned relative to design features so that the labels can be affixed to the containers with proper orientation relative to the design features. The labeled containers are again aligned and guided or conveyed past an inspection device that can be configured as a label position checker. If the label position checker detects containers with a bad or faulty label location, a signal for ejection is generated. The ejected containers are stored on a separate conveyor.
An inspection device, such as a label position checker, itself needs to be checked for correct operation. This can be done by checking the rejected containers. However this approach is very time-consuming and unreliable, in part because containers travel such high speeds. For example, many labeling machines have throughputs on the order of 16 containers per second. As a result, containers that were not rejected can only be checked randomly.
DE 10 2008 050 249 A1 relates to a test method for inspection devices, especially for label position checking devices. The test method described therein has proven to be advantageous in practice because the inspection device can be reliably checked for correct operation. The method adopted therein includes generating an individually predetermined number of test containers. These test containers are conveyed past the inspection device. If functioning correctly, the inspection device will also send a corresponding signal to an ejecting apparatus instructing it to eject at least faulty containers. An evaluator can of course be connected between the two devices. If the inspection device detects all faulty containers, and/or if all faulty test containers are ejected, and only fault-free test containers remain in the container flow, then one can infer that the inspection device is operating correctly.
According to DE 10 2008 050 249 A1, an individually predetermined number of test containers is generated manually. This means that the test containers are manually inserted into the container flow. If the test program is detected, at least the labeling function is switched off. The functional unit and/or labeling unit is automatically switched off when the test method is sequencing automatically. The test program can be run regularly, e.g. daily, before each shift change or before a product change.
The fact that only a low sampling depth can be achieved is a disadvantage because the test program is only run infrequently, for example once per shift. Manual interventions can result in increased operating errors. The issue of product liability in particular plays a part here, because a very great effort for documentation is required. A further disadvantage is that for example the labeling function is switched off when the test program is detected. However switching off the labeling function simultaneously involves a production interruption during the test and results in a loss of efficiency for the installation.